title: The metabolic basis of recovery after fatiguing exercise of human muscle.
abstract: We investigated the metabolic basis of human muscular fatigue and recovery utilizing 31P magnetic resonance spectroscopy and measurements of maximum voluntary contraction (MVC). We produced fatigue by sustained MVC for 4 minutes in 2 different muscles (adductor pollicis, tibialis anterior) and obtained similar results in both muscles. During fatiguing exercise, there was a nonlinear relationship between MVC and both phosphocreatine and total inorganic phosphate. By contrast, there was a roughly linear relationship between the decline in MVC and the accumulation of both H+ and H2PO4-. However, during recovery after exercise, MVC rapidly returned to control levels while H+ recovered with a much slower time course. On the other hand, H2PO4- rapidly returned to control values with a time course similar to MVC. In addition, the relationship of H2PO4- to MVC was similar during both fatigue and recovery. Thus, during fatigue as well as during recovery, changes in MVC correlate best with H2PO4-, suggesting that this metabolite is an important factor in human muscle fatigue.
authors.affiliation: Department of Neurology, University of California, San Francisco.
authors.forename: M D
authors.initials: MD
authors.lastname: Boska
authors.forename: R S
authors.initials: RS
authors.lastname: Moussavi
authors.forename: P J
authors.initials: PJ
authors.lastname: Carson
authors.forename: M W
authors.initials: MW
authors.lastname: Weiner
authors.forename: R G
authors.initials: RG
authors.lastname: Miller
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005221:Fatigue / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D007537:Isometric Contraction; D009682:Magnetic Resonance Spectroscopy; D009132:Muscles / Q000378:metabolism* / Q000503:physiopathology; D010710:Phosphates / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism
chemical_list: D010710:Phosphates; D010725:Phosphocreatine; D000255:Adenosine Triphosphate